relating to or denoting the current geological age, viewed as the period during which human activity has been the dominant influence on climate and the environment.
Our climate is changing: What is humanity’s role? It’s significant. How did we get here? It’s lengthy. When did we get here? It’s complicated.
The only constant in our earth’s history is change. Luckily, records of this change are present all around us—memorialized in the rocks beneath our feet, in the air above our heads, and even in the pages of our history books. The most significant record, though, can be found in the changing climates and environments of our Earth’s past. For billions of years, nature has embraced change through extended times of fire, ice, water, rocks, extinctions and renewals. However, humans have now intervened in this natural system of change. Let’s look at how and when humans began to impose their will on the planet’s climate and environment.
Setting the Anthropo-scene
4.6 billion years ago, from cosmic dust and gas our Earth emerged, thereby starting the first chapter of our planet's timeline. Early Earth’s landscape was a cauldron of chaos: raining rocks, volcanic eruptions, meteor impacts and dangerous radioactivity.
As our planet evolved, the inferno-like conditions subsided and the upper surface layers of rocks cooled into hard crusts. Oceanic basins raged with crashing waves and over time, because of scientific serendipity, life sprang.
How Do We Record Earth's History?
Geologists track our planet’s history through time scales of different lengths. Most recognizable are epochs, eons, periods, and ages; these geological times are usually in millions of years and determined by the clues contained in rock layers, ice sheets, and ocean floors. Best examples are dinosaur bones, plant fossils, and chemical residues. Collecting, interpreting, and analyzing these clues help scientists uncover evidence of past environmental conditions and climates. We are currently in the Holocene Epoch, which started about 12,000 years ago.
Started 2.6 million years ago; Ended 12,000 years ago
The Pleistocene is known for Earth’s most recent ice age. It is also known for roaming Woolly Mammoths and other megafauna, such as saber-toothed cats, giant kangaroos, and dire wolves. Towards the end of the Pleistocene, or about 200,000 years ago, Homo Sapiens emerged.
Humanity's time on the planet's clock began as our ancestors started to hunt and gather resources for survival.
Started 12,000 years ago; end TBD
By the end of the Pleistocene, our ancestors had driven the extinction of most megafauna and large swaths of glaciers had melted due to a naturally warming climate. This is also around the time that humanity developed agriculture and began the shift from primarily hunter-gatherer communities to flourishing farming communities. The promise of stable food sources drew humans away from forests and into fields.
Dawn of Human Dominance
First, let’s establish our insignificant existence in the earth’s history. We have existed for less than .05% of 1% of the earth’s history. That’s it, that’s all—a fleeting moment in billions of years.
Let’s say a mile long racetrack represents Earth’s age so far. The start of a mile is when the Earth formed, about 4.6 billion years ago. As you run along the track, you will hit multiple milestones, including the first life, the dinosaurs, the woolly mammoths, and finally, the age of humans. You will reach the age of humans at the last 2.80 inches of the racetrack.
However, humans have intervened profoundly in nature’s touchstone of constant change. In a relatively short time, as the earth's temperature should either be stable or beginning to cool, human activity is actually warming our planet at an alarming rate.
Albeit brief, the seemingly insane levels of human advancements utilized our planet’s resources—oftentimes unsustainably and with serious consequences to our planet’s physical, chemical, and ecological environments.
Let’s explore the history of human intervention called the Anthropocene.
When did the Anthropocene possibly begin?
Advancements during the Industrial Revolution most likely set the gears of the Anthropocene in motion. The promise of innovation that used new energy sources drew Europeans away from fields and into factories. Steam-powered engines using new energy resources, such as coal and oil, facilitated a significant human impact below the earth's surface.
Excavating coal and oil to generate dependable electricity left measurable signal markers in our earth’s rock layers. In addition, the burning of fossil fuels put greenhouse gases in the air, leaving clear evidence of human impacts in our atmosphere. The establishment of markers both below humanity’s feet and above humanity’s head is why scientists believe that the start of Industrial Revolution ushered in the Anthropocene.
However, the Industrial Revolution also spurred many of humanity’s greatest successes: medicines, cities, food production, electricity, education, machines, new energy sources, and indoor plumbing. These were all made possible by the technological, social and cultural advancements of the Industrial Revolution.
Essentially, the economy was and still is a function of the environment.
One must understand that the usage of the environmental resources drove positive technological advancements of the Industrial Revolution. Essentially, the economy was and still is a function of the environment.
The Industrial Revolution developed significant wealth in Western cultures. This wealth led to another possible starting time of the Anthropocene called the Great Acceleration. During the great acceleration, human population doubled in size from 3 billion to 6 billion. This dynamic growth led to human impacts on every natural system on earth. More demands for clean water, dependable energy, adequate food and comfortable shelter produced the social and geological markers, signaling a new era.
Population growth through the Great Acceleration
Some think the Anthropocene began when the United States first detonated a nuclear bomb in the New Mexico desert. The chemical residues left in the earth from this destructive technology may have signaled the start of the Anthropocene. Plutonium-239, rare in nature but abundant in above-ground nuclear weapons fallout, is a suitable chemical signature. It is not easily soluble and has a long half-life, which means it will be present in the depths of the earth for a long time.
Has a new geologic timescale started?
Yes! As we trace the footprints of humans past, we find the fingerprints of human impacts today. These fingerprints signal the start of a new geological time called the Anthropocene. The Anthropocene balances a delicate and complicated tension in our Earth’s history as we see the profound environmental impacts of whole scale land change, species extinctions, chemicals in our geological layers, greenhouse gases in our atmosphere, and acid in our oceans.
Here are a few more defining inventions of the Anthropocene:
Yet humans have pressed relentlessly forward, cultivating and inventing transformative technological advancements that have taken our species from the caves of Africa to the depths of the Milky Way. Pretty cool.
Still, it is up to us to determine where our species will go from here. A sustainable, safe and optimistic future well into the Anthropocene is ours should we choose to embrace it.